The invention pertains to a configuration based cooling fan speed control, and more particularly, to a method and apparatus for controlling an electronic device's cooling fan speed using a programmable EEPROM which is writable through limited access firmware controls.
As electronics enter the submicron age, smaller, more closely packed conductors are performing more operations at higher speeds. One byproduct of this technological advancement is heat. Heat is typically removed with the assistance of one or more cooling fans mounted in close proximity to a device's heat producing components. However, while conductor technology has advanced significantly, fan technology has not.
Most conventional fans are run at a constant voltage. The fans and their operating voltages are chosen so that adequate airflow/cooling is guaranteed for a device's worst case configuration and ambient conditions. For most configurations and ambient conditions, this means providing more airflow, and thus more audible noise, than is needed. For a device requiring relatively large cooling fans, this noise can reach a bothersome level.
Some fans provide a means of ramping up fan speed based on changes in ambient conditions (i.e., air temperature). However, the fans are still configured so as to always assume a worst case of operating conditions. Thus, a fan's thermal ramp begins at a relatively high speed, and the airflow and acoustic noise produced by the fan are still significantly greater than are required.
It is therefore a primary object of this invention to provide a cooling fan speed controller which is capable of adjusting a fan's settings for a wide range of product configurations.
It is also an object of this invention to provide a cooling fan speed controller which relies on programmable firmware controls.
It is a further object of this invention to provide a fan which minimizes acoustic noise emissions.